title: Physicochemical and functional properties of beany flavour-free bambara groundnut protein isolate.
abstract: BACKGROUND
  Off-odour/flavour (beany) associated with bambara groundnut protein isolate (BGPI), due to oxidative degradation of lipids during either storage or processing, is a major problem limiting its application in foods. In this study, effects of heat treatment (50-80 °C) in combination with ethylenediaminetetraacetic acid (EDTA) on functional and sensory properties of BGPI were investigated.
  
  
  RESULTS
  BGPI prepared in the presence of EDTA had lower lipoxygenase and trypsin-inhibitory activities than BGPI prepared in the absence of EDTA, regardless of the heating temperature used (P < 0.05). Inactivation of lipoxygenase was associated with lowered peroxide value, thiobarbituric acid-reactive substances and beany odour/flavour intensity in BGPI stored at room temperature for 30 days. BGPI with heat treatment at temperatures lower than 70 °C had similar protein patterns to BGPI prepared by the typical process, except for the occurrence of proteins with molecular weight 70-82 kDa. BGPI with heat treatment showed decreased protein solubility but increased surface hydrophobicity and sulfhydryl group content. BGPI prepared in the presence of EDTA exhibited higher emulsion activity and stability indices as well as higher foam expansion and stability than BGPI prepared in the absence of EDTA, regardless of heating temperature (P < 0.05).
  
  
  CONCLUSIONS
  Heat treatment at 70 °C in the presence of 100 mmol L(-1) EDTA effectively reduced beany flavour development and enhanced the functionality of BGPI.
authors.affiliation: Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, 90112, Thailand.
authors.forename: Tanaji G
authors.initials: TG
authors.lastname: Kudre
authors.forename: Soottawat
authors.initials: S
authors.lastname: Benjakul
mesh_terms: D004032:Diet; D004044:Dietary Proteins / Q000737:chemistry*; D004492:Edetic Acid; D004655:Emulsions; D004791:Enzyme Inhibitors / Q000737:chemistry; D007887:Fabaceae / Q000737:chemistry*; D005511:Food Handling / Q000379:methods; D061353:Food Storage; D006358:Hot Temperature; D006801:Humans; D015227:Lipid Peroxidation; D008084:Lipoxygenase / Q000378:metabolism*; D009812:Odorants; D010545:Peroxides / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry; D012639:Seeds / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000032:analysis; D013649:Taste; D014357:Trypsin / Q000378:metabolism
chemical_list: D004044:Dietary Proteins; D004655:Emulsions; D004791:Enzyme Inhibitors; D010545:Peroxides; D010940:Plant Proteins; D013438:Sulfhydryl Compounds; D004492:Edetic Acid; D008084:Lipoxygenase; D014357:Trypsin
keywords: EDTA; bambara groundnut; beany flavour; functional properties; heating; lipoxygenase; protein isolate